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TITLE 30ENVIRONMENTAL QUALITY
PART 1TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 290PUBLIC DRINKING WATER
SUBCHAPTER FDRINKING WATER STANDARDS GOVERNING DRINKING WATER QUALITY AND REPORTING REQUIREMENTS FOR PUBLIC WATER SYSTEMS
RULE §290.107Organic Contaminants

(a) Applicability. All community and nontransient, noncommunity water systems shall comply with the requirements of this section regarding organic contaminants. For purposes of this section, systems using groundwater under the direct influence of surface water shall meet the organic sampling requirements given for surface water systems.

(b) Maximum contaminant levels (MCLs) for organic contaminants. The concentration of synthetic and volatile organic chemicals shall not exceed the MCLs specified in this section.

  (1) The following are MCLs for synthetic organic chemical (SOC) contaminants.

Attached Graphic

  (2) The following are MCLs for volatile organic chemical (VOC) contaminants.

Attached Graphic

  (3) Each public water system must certify annually to the executive director (using third-party or manufacturer's certification) that when acrylamide or epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed 0.05% dosed at 1.0 milligrams per liter (mg/L) (or equivalent) for acrylamide and 0.01% dosed at 20 mg/L (or equivalent) for epichlorohydrin.

(c) Monitoring requirements for organic contaminants. Public water systems shall monitor for organic contaminants at the locations and frequency in paragraphs (1) and (2) of this subsection. All monitoring conducted under the requirements of this section must be conducted at sites designated in the public water system's monitoring plan. All samples must be taken during periods of normal operation.

  (1) SOC monitoring requirements. Monitoring of the SOC contaminants shall be conducted at the frequency and locations given in this paragraph.

    (A) SOC monitoring locations. Monitoring of the SOC contaminants shall be conducted at the following locations.

      (i) Systems shall routinely sample at sample sites representative of each entry point to the distribution system.

      (ii) Subsequent samples must be taken at the same sample site unless the executive director determines that a change in conditions makes a different sample site more representative of the water available to customers.

      (iii) The executive director must approve any change in sampling location.

    (B) Initial SOC monitoring frequency. Prior to using a new source of water as drinking water, public water systems shall monitor at the frequency established by the executive director to ensure that the water distributed to customers will comply with the MCLs for SOCs.

    (C) Routine SOC monitoring frequency. Monitoring of the SOC contaminants shall be conducted at the following frequency.

      (i) Community and nontransient, noncommunity water systems shall take four consecutive quarterly samples for each SOC contaminant listed in subsection (b)(1) of this section during each compliance period beginning with the initial compliance period.

      (ii) Community and nontransient, noncommunity water systems serving more than 3,300 persons that do not detect a contaminant in the initial compliance period may reduce the sampling frequency at that sample site to a minimum of two consecutive quarterly samples in one year during each repeat compliance period.

      (iii) Community and nontransient, noncommunity water systems serving 3,300 persons or fewer that do not detect a contaminant in the initial compliance period may reduce the sampling frequency at that sample site to a minimum of one sample during each repeat compliance period.

      (iv) Each public water system shall monitor at the time designated by the executive director within each compliance period.

    (D) Increased SOC monitoring. The executive director may change the monitoring frequency for SOCs.

      (i) Entry points that exceed the SOC MCLs of subsection (b)(1) of this section as determined by subsection (f) of this section must be monitored quarterly. After a minimum of four quarterly samples shows the system is in compliance and the executive director determines the system is reliably and consistently below the MCL, as determined by the methods specified in subsection (f) of this section, the executive director may allow the system to monitor annually. Systems that monitor annually must monitor during the quarter that previously yielded the highest analytical result.

      (ii) The executive director may change the monitoring frequency if an organic SOC contaminant is detected in any sample.

        (I) If an organic SOC contaminant is detected in any sample, the system must monitor quarterly at each entry point to the distribution system at which a detection occurs.

        (II) After a system collects a minimum of two consecutive quarterly samples at a groundwater sample site, the executive director may decrease the quarterly monitoring requirement specified in subclause (I) of this clause, if the sample site is reliably and consistently below the MCL.

        (III) After a system collects a minimum of four consecutive quarterly samples at a surface water sample site or a groundwater under the direct influence of surface water sample site, the executive director may decrease the quarterly monitoring requirement specified in subclause (I) of this clause, if the sample site is reliably and consistently below the MCL.

        (IV) After the executive director determines that a sample site is reliably and consistently below the MCL, the executive director may allow the sample site to be monitored annually. Systems that monitor annually must monitor during the quarter that previously yielded the highest analytical result.

        (V) Sample sites that have three consecutive annual samples with no detection of a contaminant may be granted a waiver at the discretion of the executive director. The executive director will consider the waiver for each compliance period.

        (VI) If monitoring results in detection of one or more of certain related contaminants (i.e., heptachlor and heptachlor epoxide), then subsequent monitoring shall analyze for all related contaminants.

      (iii) The executive director may increase the required SOC monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal use, changes in water source, etc.).

      (iv) The executive director may require a confirmation sample for positive or negative results. If a confirmation sample is required by the executive director, the result must be averaged with the first sampling result and the average used for the compliance determination as specified in subsection (f) of this section. The executive director has discretion to delete results of obvious sampling errors from this calculation.

    (E) Waivers for SOC monitoring. The executive director may grant a waiver to reduce the SOC monitoring frequency from the monitoring frequency requirements of subparagraphs (B) and (C) of this paragraph, based on previous use of the contaminant within the watershed or zone of influence of the water source. Examples of use of a contaminant include transport, storage, or disposal. If a determination by the executive director reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be granted. If the executive director cannot determine whether the contaminant has been used in the watershed or if the contaminant has been used previously, then the following factors shall be used to determine whether a waiver is granted:

      (i) previous analytical results;

      (ii) the proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at drinking water sources, manufacturing, distribution, or storage facilities, or from hazardous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources include the use of pesticides to control insects, weeds, or pests on agricultural areas, forest lands, home and garden property, or other land application uses;

      (iii) the environmental persistence and transport of the pesticide herbicide or contaminant;

      (iv) how well the water source is protected against contamination due to such factors as depth of the well, type of soil, and the integrity of well construction. Surface water systems must consider watershed vulnerability and protection;

      (v) elevated nitrate levels at the water supply source; and

      (vi) use of polychlorinated byphenyls (PCBs) in equipment used in the production, storage, or distribution of water (i.e., PCBs used in pumps, transformers, etc.).

    (F) Compositing for SOC monitoring. The executive director may reduce the total number of samples required from a system for analysis by allowing the use of compositing. Composite samples from a maximum of five entry points to the distribution system are allowed. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.

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